Inorganic Chemistry最新文献

Open d-shell transition-metal oxides are widely studiedas photoactivematerials for solar-energy conversion but typically exhibit low yieldsof mobile photocarriers. This inefficiency has been linked to ligand-field(LF) states that induce ultrafast relaxation, although their impactacross open d-shell oxides remains poorly understood. Here, epitaxialilmenite-type MTiO₃ (M = Ni, Co, Mn) thin films were stabilizedby pulsed laser deposition. In this isostructural series, the M²⁺ cation tunes the d-electron configuration and the energeticseparation and spectral overlap of LF and charge-transfer excitations.Combined optical and time-resolved microwave conductivity measurements,benchmarked against rutile TiO₂ as a d⁰ reference,together with photoelectrochemical measurements of the ilmenites,reveal reduced yield-mobility products compared to TiO₂. NiTiO₃ and CoTiO₃ show measurable photoconductivityonly under UV charge-transfer excitation, whereas MnTiO₃, dominated by a dense LF manifold, exhibits a negligible response.These results indicate that mobile charge-carrier generation contributingto photoelectrochemical activity originates from UV charge-transferexcitations, likely dominated by O^2– → Ti⁴⁺ ligand-to-metal charge-transfer (LMCT) excitation into Ti3d-derived states, while LF states primarily act as relaxation pathwaysthat do not yield mobile carriers on nanosecond time scales. Thesefindings decouple the roles of distinct optical excitations in governingphotocarrier localization in open d-shell oxides.

Natural gas, as a clean energy source, requires the eliminationof co-occurring impurities such as C₂H₆ andC₃H₈ to enhance its energy utilization efficiency.Herein, by using a Zr-based MOF as a platform, we fabricated an isostructuralpair, NU-1400(−H) and fluorine-functionalized NU-1400(−F), through rational ligand fluorination,and systematically investigated their adsorption and separation performancestoward CH₄, C₂H₆ and C₃H₈. This isostructural pair allows the effect of fluorinefunctionalization on the pore microenvironment and adsorption affinityto be directly evaluated. Single-component adsorption isotherms revealthat fluorine functionalization significantly improves the uptakecapacities of C₂H₆ and C₃H₈ (from 25.4/28.8 to 34.1/38.9 cm³ g^–1), while causing only marginal changes in CH₄ adsorption.Isosteric heat of adsorption (Q_st) analysisconfirms that NU-1400(−F) exhibits weakened affinityfor CH₄ (19.2 kJ mol^–1) and remarkablyenhanced interaction with C₃H₈ (47.3 kJ mol^–1). Benefiting from such optimized differences in adsorptionaffinity, NU-1400(−F) achieves excellent IASTselectivity of 516 for C₃H₈/CH₄ and21 for C₂H₆/CH₄, which are far higherthan those of pristine NU-1400(−H) (145 and 18).Dynamic breakthrough experiments and cyclic regeneration tests furthervalidate its reliable separation capability and outstanding recyclability.The rational fluorine functionalization effectively tailors the poremicroenvironment for selective heavy-hydrocarbon adsorption, making NU-1400(−F) a promising adsorbent for one-step methanepurification from natural gas. This work thus highlights a practicalpore-microenvironment engineering strategy via ligand fluorinationfor efficient light hydrocarbon/CH₄ separation.

Crystals formed in aqueous solutions often encode chemicalmemoriesof their growth environment. However, the molecular pathway of elementpartitioning that links solution chemistry to solid composition remainselusive when growth proceeds through nonclassical intermediates. Inthis study, we investigated calcite growth mechanisms in the presenceof aqueous manganese (Mn²⁺) under chemostat conditionsusing a custom titration method. At near-neutral pH, where bicarbonateions dominate, we show that Mn²⁺ triggers the formationof bicarbonate-rich, ion-paired liquid condensates that accumulateat the calcite–water interface and control Mn incorporationinto the solid phase. Time-resolved in situ X-ray scattering and Ramanspectroscopy, combined with cryogenic transmission electron microscopyand molecular dynamics simulations, reveal a pathway in which thesecondensates deprotonate and dehydrate into Mn-bearing amorphous carbonatethat crystallizes into polycrystalline calcite–rhodochrositeinterfacial solid solutions with progressively increasing Mn content.These results identify an interfacial, bicarbonate-rich liquid condensateas a mechanistic link between crystallization pathway and elementpartitioning, suggesting that nanoscale interfacial fluid organizationcan dominate selective ion uptake during crystallization in multicomponentaqueous environments that are relevant to geoscience, environmentalscience, chemistry, or materials science.

Copper is an essentialelement involved in several cofactorsandorganometallic compounds used as catalysts. Although most biologicalcopper centers contain one to three copper ions, nature has evolveda unique tetranuclear copper–sulfur cluster that has attractedthe attention of both biochemists and inorganic chemists. This multinuclearcopper center has only been observed in one enzyme, nitrous oxidereductase, which catalyzes the reduction of nitrous oxide to dinitrogen,the final step of the denitrification pathway. The structural, spectroscopic,and kinetic properties of this [4CuS] cluster have been the subjectof extensive investigation, revealing that it exists in two distinctforms within the enzyme, CuZ[4Cu:2S] and CuZ*[4Cu:1S], with differentoxidation states, spectroscopic signatures, and catalytic properties.These features are discussed together with recent advances in understandingthe biosynthesis and assembly of this cluster. Inorganic chemistshave synthesized a variety of structural and functional models ofthe CuZ cluster, although none fully reproduces the electronic structureand catalytic efficiency of the native active center. This reviewdiscusses the interplay between biological and synthetic studies,illustrating how advances in one field continue to inspire progressin the other while identifying the challenges that must be overcometo achieve truly functional biomimetic catalysts.

Solvated electronprecursors (SEPs) are coordinationcomplexesthat accommodate one or more electrons in diffuse, hydrogenic-typeorbitals at the periphery of the molecular skeleton. Prototypicalmetal–ammonia complexes, observed in both gas and condensedphases, serve as building units for a novel class of electrides. AnchoringSEPs to inert surfaces (surface-immobilized SEP electrides, SISEPEs)offers materials suited for redox catalysis and quantum computinghardware. The titled (NH₃)₅MCH₃ speciesserve as a model for the active sites of SISEPEs. To characterizetheir electronic structure and stability, high-level wavefunctionand density functional theory calculations are performed for M = Sc,Ti, V, and Cr. Beyond the valence 3d electrons, thesecomplexes host one electron in hydrogenic-type diffuse peripheralorbitals, with low-lying electronic states populating the 1s, 1p,1d, and 2s outer diffuse orbitals. Compared to the corresponding purehexacoordinated metal–ammonia complexes, (NH₃)₅MCH₃ disfavors migration of an ammonia ligand tothe second solvation shell, and the diffuse electron density is polarizedaway from the methyl ligand. These findings provide a theoreticalframework for designing and characterizing SISEPE materials and highlightthe role of the M-C bond in modulating stability, electronic excitationpatterns, and the spatial characteristics of the outer diffuse orbitals.

Ionicplastic crystals (IPCs) exhibit long-range translationalorder with orientational disorder and enhanced molecular mobility,yet their chemical reactivity remains unexplored. Salts of the sandwich-typeRu complex cation [Ru(Cp)(C₆H₆)]⁺ ([1]⁺) often exhibit IPC phases, while cyanoboratesalts of [1]⁺ undergo photochemical reactionsto form polynuclear complexes in solution and in the ionic-liquidstate. These properties prompted us to synthesize [1]BE(CN)₃ (E = F, H, or Me) and [1]BE₂(CN)₂ (E = F or Et) and investigate their phase behavior and photoreactivityin IPC phases. All five salts exhibited IPC phases, with transitiontemperatures from the low-temperature crystalline phase to the IPCphase ranging from 277 to 378 K; three underwent the transition below300 K. UV irradiation of these three salts in their IPC phases affordedcubane-type tetranuclear complexes from [1]BF(CN)₃ and [1]BH(CN)₃ with conversions of50–77%, whereas [1]BF₂(CN)₂ gave an anionic dinuclear complex along with decomposition products.In contrast, irradiation of [1]BH(CN)₃ and[1]BMe(CN)₃ in their low-temperature crystallinephases gave conversions of only 18% and 11%, respectively. These resultsdemonstrate that the high molecular mobility of IPCs enables solid-statephotochemistry, with the salts acting as both reactants and reactionmedia.

Borohydrides are widely used sources of hydride ions(H^–), but their conventional synthesis from highlyreducing metal hydridesis energetically demanding and undermines sustainable applications.Herein, we report a sterically encumbered thioether-substituted triarylborane, 1,2-(^tBuS)C₆H₄(BMes₂) (3) (Mes = 2,4,6-Me₃C₆H₂), which is highly air- and moisture-stable. 3 exhibits a one-electron reduction at E⁰ = −2.62 V vs Fc^+|0 and a radical anionhalf-lifetime of ∼0.5 s in THF, enabling bimolecular follow-upreactivity. Indeed, two-electron reduction and protonation of 3 with KC₈/[DBUH]⁺ (DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene)or hydride transfer from Li(AlH₄) affords the borohydride 4^–. From a hydricity–potentialcorrelation, we estimate a hydricity of ∼36 kcal mol^–1 in MeCN, which allows 4^– to reduce H⁺ to H₂ and CO₂ to formateunder ambient conditions in almost quantitative yields. The reactionof 3, [DBUH]⁺, KC₈, and CO₂ furnishes potassium formate in ∼90% spectroscopicyield, establishing a closed synthetic cycle for CO₂ reductionby protons and electrons at a boron center. These results highlighthow tailor-made, redox-active boranes can complement transition-metalhydrides as modular, metal-free platforms for coupling renewable electronsand protons in CO₂ utilization chemistry.

Lanthanide contraction provides a continuous scale fortuning coordinationstructures, yet its systematic use in photoactive materials remainsunderexplored. Herein, 14 POM-phosphonate-lanthanide hybrids fromLa to Lu (excluding Pm) were synthesized under mild conditions. Single-crystalXRD identifies three coordination regimes: La³⁺ at theeight/nine-coordination boundary, Ce³⁺-Yb³⁺ adoptingstable eight-coordination, and Lu³⁺ undergoing a ligand-deficienttransition due to steric congestion. The Sm³⁺ complex 5b, obtained under diffusion conditions, exhibits the samemotif as Lu³⁺ complex, indicating that crystal growth conditionscan influence coordination-mode selection. Combined with band-structureanalysis, EIS, radical trapping, EPR, and HPLC-MS, the photocatalyticmechanism was investigated. This work converts lanthanide contractionfrom a descriptive concept into an experimental framework for constructingstructure-performance correlations.